Which quality marks exist?

RAG landscaping, RAG green roof and RAG SOIL SUPPLY are the three quality marks for the landscaping segment

The RHP foundation manages two quality marks: RHP and RAG. The certification has six different fields of application, each with its own spearheads, products and certified companies. For you as entrepreneur in the landscaping segment, the three quality marks below are valuable:

  • RAG Landscaping
  • RAG Green Roof
  • RAG Soil Supply

RAG Landscaping

RAG Landscaping is the quality mark for public green spaces. The RAG quality mark certifies soil products that are intended for professional growers, authorities, park managers, contractors of infrastructure and gardeners. The requirements that the RAG Landscaping quality mark puts to tree substrate go beyond the RAW guidelines. As a result you can trust that the certified companies have done everything to make sure that all delivered products:

  • offer the utmost security because both the product and the process in the whole chain is monitored,
  • are free from quarantine diseases,
  • are lacking weeds
  • comply with a maximum salt content,
  • comply with the legal requirements concerning contaminations with heavy metals, PAK’s and mineral oil.


Why does the tree not grow?

It’s ok for the most part, but sometimes things go wrong. Trees that don’t want to grow well and healthy or are decaying for years and finally die. Then find out the cause when all plant diseases are out of the question. After examination of one of the employees of RHP/RAG it becomes clear, that the problem was caused by using a qualitatively inferior soil and/or structure improvers. Sometimes the cause is tree sand, that is unsuitable for that specific application, as a result of which the roots of a tree grow in too dry or too wet conditions. Sometimes the cause is the use of an insufficiently stable compost, resulting in a root environment that is lacking oxygen. That’s why it is essential to start with materials that have the RAG Landscaping quality mark, because a good soil and structure improver is more important than you think.


Always contemporary and up-to-date

RAG Landscaping is a quality mark in motion. New substrates that are allowed to carry the RAG Landscaping quality mark are continuously launched on the market. Think for instance of dress soil for golf courses and lava substrate as foundation for paved roads. RAG stands for a dynamic quality mark that knows the developments in practice and initiates test methods to support them.

RAG Green Roof

The quality mark RAG Green Roof offers more security for the use of a qualitative good green roof substrate. The nutrition in the green roof substrate is balanced, through which the plants take advantage of the optimal basis for a lifetime as long as possible.

The RAG Green Roof puts clear requirements to the green roof substrate. As a result you can trust that the certified companies have done everything to make sure that all delivered green roof substrates:

  • are clean (among others free from human pathogens) and lacking weeds
  • have an optimal oxygen content, through which the plants get the most favourable basis for a lifetime as long as possible
  • comply with the environmental standards (among others no heavy metals)
  • have an optimal buffering / water buffering capacity, that complies with the strict requirements of the independent control. The RAG green roof substrate combines water buffering with physical properties for an optimal growth.
  • restrict the pressure on the city sewer by dosed water drainage
  • have a warmth and noise isolating effect. As a result gas and heating costs can be saved and costs of the air conditioning can be decreased.


Urban Farming in a green city

To retain green spaces in the city, the multifunctional use of space is necessary. The application of green roofs and facades is a good way of extending green spaces in cities. The covering of facades and roofs makes the city healthier, greener and more functional. Think of urban farming at this, where RAG certified substrates guarantee a safe start to grow vegetables. Overgrown roofs are also very suitable places where you can lunch, work or relax pleasantly. In short, the living - and working climate improves.


A unique quality assurance system in the whole chain

Suppliers, producers and traders must comply with the quality requirements of RAG Green Roof to be able to carry the quality mark. These strict requirements concern:

  • physical properties, among others optimal air – and water system,
  • chemical properties, among others balance in applied nutrition,
  • phytosanitary properties, like prevention of diseases.


The unique quality assurance system of RAG Green Roof is a track through the chain, as a result of which risk factors are excluded at an early stage. The whole chain, from raw materials to substrate producer, to user, is continuously controlled by means of periodic examination.

RAG Soil Supply

The quality mark RAG Soil supply offers more security that there are excellent soil supply and soil improving materials. To prevent wear of the soil, soil supply and/or soil improvers are applied. These RAG certified products repair the soil structure and provide the utmost security on:

  • better growth conditions,
  • good air- and water system in the tilth of the soil,
  • regular supply of nutrient in the soil.


Nothing may be left to chance at soil improving. The quality mark RAG Soil supply put strict requirements to the soil supply and soil improvers. As a result you can trust that the certified companies have done everything to make sure that all raw materials and substrates:

  • offer the utmost security because the quality of both the product and the process in the whole chain is controlled by means of tracking & tracing.
  • are tested on chemical, physical and phytosanitary requirements and therefore are free of the most occurring quarantine diseases. You can always request an analysis report to your supplier,
  • are lacking weeds. The raw materials that are used for producing substrates are tested on the quantity germinative weed seeds. If the standards are exceeded, then these materials are rejected for the application of the RAG quality mark.


Organic matter content essential for healthy soil

One of the most important parts of a healthy soil is the organic matter content, because:

  • Organic matter is necessary for a good connection between soil parts and moisture retaining capacity.
  • A good organic matter content raises the capacity for binding nutrients.
  • Decomposed organic matter inhibits the development of pests and diseases.


In short, a well adjusted organic matter content results in:

  • Good root system,
  • Healthy air system,
  • Fine processability of the soil.

Soil supply and soil improvers with the RAG quality mark provide a proved contribution to the development of the appropriate organic matter content in the soil.


Which soil improver is necessary?

By means of a soil analysis, it is determined which soil property has to be improved to come to the desired culture result. Think of:

  • Improvement of the processing of the soil
  • Improvement of the buffering of moisture
  • Improvement of the drainage of moisture

When this is known, the suitable soil improver is chosen.

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